The present invention relates to hydrolyzable and polymerizable silanes, methods of making them and methods of using them to make silicic acid polycondensates and/or-heteropolycondensates and polymerizates and/or heteropolymerizates.
Hydrolyzable, organically modified silanes have various applications in the manufacture of scratch-resistant coatings for different substrates, for making filling materials, adhesive and sealing materials or molded bodies. In those applications the silanes, either alone or in mixtures with each other or in the presence of additional hydrolyzable and/or condensable components, are hydrolytically condensed. The final hardening occurs thermally, photochemically, covalent-nucleophilically or is redox induced.
Thus scratch resistant coatings which are described in German Patent DE 3407087 C2 are formed by hydrolytic condensation and comprise, e.g., a hydrolyzable titanium or zirconium compound and a hydrolyzable, organo-functional silane EQU R'.sub.m (R"Y).sub.n SiX.sub.4-m-n,
wherein R' represents, e.g., alkyl or alkenyl, R" represents, e.g., alkylene or alkenylene, and X represents a hydrolyzable group.
Adhesive and sealing materials are described in German Patent DE 3536716 A1 which could be obtained by hydrolytic condensation of one or more organosilanes of the general formula R.sub.m SiX.sub.4-m and, as needed, one or more of the components SiX.sub.4 and/or R.sub.n (R"Y).sub.p SiX.sub.4-n-p, wherein R and R" are independently, e.g., an alkyl group, alkenyl group, aryl group, alkylaryl group or an arylalkyl group; X is hydrogen, halogen, a hydroxy group, an alkoxy group or acyloxy group; and Y is a halogen or an unsubstituted or substituted amino, amide, aldehyde, alkylcarbonyl, carboxy, hydroxy, mercapto or cyano group.
Commercial silanes with reactive double bonds are known, such as (meth)acryloxysilanes of the following formula: EQU CH.sub.2 .dbd.CR--CO--O--(CH.sub.2).sub.3 --SiX.sub.3
wherein R is hydrogen or methyl and X is , e.g., halogen or alkoxy. These silanes are hydrolyzable and polymerizable and can be used for manufacture of the above-described systems. They offer the great advantage that the resultant coating, the resultant filling material, adhesive material, sealing material or the resultant molded body can be hardened thermally, photochemically, covalent-nucleophilically or can be redox induced by polymerization at the reactive double bond.
Commercial silanes with reactive double bonds, such as the above-described (meth)acryloxysilanes, are in general monofunctional compounds with one C.dbd.C double bond and are comparatively low molecular weight and thus comparatively volatile compounds prior to the Si--X hydrolysis and condensation, which are toxicologically hazardous because of the acryl group present. During further processing by polymerization or by modifying functional groups these silanes also have the disadvantage that only chain polymers can be obtained because of the presence of only one reactive double bond and in the above-mentioned modification of functional groups these C.dbd.C double bonds required for the organic polymerization are usually lost. Furthermore only one short chain is usually found between the double bonds and the silicon enabling the formation of an inorganic network, so that the mechanical properties (flexibility etc) are only changeable to a limited extent by the organic groups.
Of course hydrolyzable and polymerizable silanes, which provide more than one reactive C.dbd.C double bond, are described in German Patent 4011044 C2, and in which the spacing between the reactive double bond and the silicon enabling the formation of the inorganic network is comparatively longer, although still in need of improvement. Also improvement in the functional groups of the molecule would be desirable.